1. Field of the Present Invention
The present invention relates generally to support housings for electrical outlets and switches and more particularly to the means for attaching a cover plate to a wall mounted electrical box housing.
2. Description of the Prior Art
Wall mounted electrical box housings for switches, plug outlets and the like are often covered by a cover plate which extends over the hole in the wall in which the electrical box is mounted. Such cover plates often include apertures of a desired shape and size to permit exposure of electrical outlet or switch levers through the opening so that the outlets or levers remain accesible for use. The most common means for securing the cover plate to the electrical box housing is to provide the cover plate with mounting apertures adapted to receive a threaded fastener which extends through the mounting apertures in the cover plate and is threadably engaged within apertures of threaded bores formed in the electrical box housing. The threaded fasteners are typically headed screws which require the use of a screwdriver to install and remove the cover plate. Moreover, the production of threaded apertures in the electrical box housing substantially increases the cost and complexity of production of the electrical box housing. Nevertheless, it is important that the cover plate remain stabily secured to the electrical box housing to avoid exposure of the hole in the wall around the electrical box housing and to protect the electrical components supported therein.
Since it is desirable to remove the cover plates when the building walls are being painted or when the electrical circuitry in the electrical box housing is being repaired or inspected, the commonly utilized screw type attachments for the cover plates prolong the time necessary to complete the work. Moreover, withdrawal and installation of the screws through the cover plates requires the use of a tool such as a screwdriver, and thus further prolongs and complicates the task of removing the cover plates.
Although there have been some previously known detachable cover plates which do not require the use of tools, these devices also suffer the disadvantage of complicated construction, and are not often applicable to the existing electrical box housings which are in common use. For example, U.S. Pat. No. 3,155,808 to Wiley discloses a fastener for a cover plate in which the cover plate is provided with a pair of projections adapted to be received in specially constructed apertures in the switch housing. Although the construction of the projections is rather simple, the apertures in the housing must be provided with a rim having radially inwardly extending barbs in order to retain the projections within the aperture. Such a construction requires mating construction of both the cover plate and the housing and thus increases the cost and complexity for each of the components. Morevoer such a cover plate is not interchangeable with previously known cover plates for covering the commonly utilized electrical box housings.